As spotted owl’s numbers keep falling, some fear it’s doomed

Originally published August 13, 2008 at 12:00 am
Updated August 13, 2008 at 9:55 am

Buffeted by years of logging and the invasion of a tougher owl, populations of the northern spotted owl are falling year after year, despite sweeping protections for the old-growth forests it inhabits. Now, genetic problems are adding to the reasons for worry. A just-released study found the remaining birds are so genetically similar, they are...

The situation is particularly bad in Washington, where the rate at which owls are found at nesting sites has fallen by nearly half since 1994. Scientists blame the decline largely on the invasion of a tougher owl and the loss of much habitat to decades of logging.

“It’s not looking very good,” said Eric Forsman, of the U.S. Forest Service, a pre-eminent spotted-owl scientist. “The populations seem to be gradually going downhill, and it’s not clear if or when that’s going to stop.”

The decline of the birds is forcing a rethinking of long-held strategies to save the spotted owl. Ideas under consideration include the distasteful prospect of shotgunning one owl species to save another.

It could also rekindle the old-growth logging debate. Since the bird was a chief tool for environmentalists to block logging, what happens if there are no spotted owls left in a forest?

Plan hasn’t worked

Back in 1994, few could have foreseen things turning out this way.

The Clinton administration — spurred by lawsuits, the listing of the owl under the Endangered Species Act, and years of political upheaval over Northwest logging — set aside 24.5 million acres of federal forestland as a haven for the owls.

The Northwest Forest Plan was supposed to set the stage for recovery of the football-sized bird, which favors older forests because it nests in the cavities of big trees, and eats forest-dwelling creatures such as flying squirrels.

But the recovery hasn’t happened.

It’s unknown exactly how many spotted owls there are. Scientists take the bird’s pulse by monitoring huge patches of forest from Washington’s Cascades to Northern California.

In every one of those places, there are more empty nests today than in 1994.

Harder to find

Dale Herter has grown accustomed to disappointment.

Every year the wildlife biologist returns to the forests north of Mount Rainier to track spotted owls. All too often, a nest occupied the year before is silent.

In the 16 years since he first started cruising the woods, hooting like a spotted owl and listening for a response, Herter has seen the population drop by half.

“Within a decade we may not have any in Washington unless they do something,” said Herter, who works for the Seattle environmental consulting firm Raedeke Associates.

On a recent day, crouched on a steep hillside in the Mount Rainier foothills, he came eye to eye with one of the last hopes for spotted owls there.

Herter perched a white mouse on a stump. Within seconds, the mouse disappeared in a hushed blur of talons and brown and white feathers. A female spotted owl winged between the branches of Douglas firs, clutching her prey.

Herter scrambled to a dirt road, striding along to track the owl.

“I see a baby,” announced fellow birder Alan Grenon.

“That’s cool, at least one survived,” Herter said.

“Oh, there’s two,” Grenon called out.

These fledglings were two of 10 Herter counted. It’s the fewest he’s found during a peak year, when the owls should be most productive.

Genetic “bottleneck”

The magnitude of the problem was confirmed by a new analysis of spotted-owl genetics.

With little fanfare, federal scientists in July publicly released a study warning that northern spotted owls, particularly in Washington, have reached a “population bottleneck.”

The remaining birds are genetically similar enough that there’s a heightened risk of inbreeding, the study found. The bottleneck also threatens the genetic diversity that helps a species adapt to changing circumstances.

It’s not clear if this is already a reason owl populations are falling. But the authors said we could be witnessing a bird in a downward spiral, exacerbated by a shrinking gene pool, known as an extinction vortex.

“I have not lost hope for spotted owls. But I think we’re at a pretty serious crossroads,” said Susan Haig, a wildlife geneticist with the U.S. Geological Survey and one of the study’s authors.

Forsman, however, said it’s too soon to predict the owl’s fate. There are still sizable spotted-owl populations, particularly in southern Oregon and Northern California. Spotted owls might also change their behavior in some way that enables them to survive.

“There’s no way at this point to predict how this will ultimately play out.”

Owl competitor

Scott Gremel points the finger at one chief culprit for what he’s witnessed in Olympic National Park: the barred owl.

Bigger, more versatile and able to hatch more offspring, the barred owl could hardly be better suited to compete with spotted owls.

Gremel, a biologist who has tracked the owls in Olympic National Park since the 1990s, has an unusual vantage point. Clear-cuts haven’t threatened owls in the park’s protected forests.

Yet their numbers keep dropping as barred owls move into valley after valley. Last year, just 37 percent of the places in the park where spotted owls once nested were still occupied by the birds.

“Someone described it as a bathtub. It’s just filling up with barred owls,” he said.

Across the West Coast, the barred owl is a prime suspect in the spotted owl’s disappearance.

Native to the East Coast, it’s thought to have reached the West Coast in the mid-1900s via forests in Canada. But it wasn’t until the 1960s and 1970s that it first was seen in Washington and Oregon, and in the last two decades its numbers have exploded.

Some researchers caution that it’s still not known how much havoc the barred owl is causing.

Spotted owls are also vulnerable to harsh winters, loss of old-growth habitat to forest fires, and continued logging. Some of the decline might be an aftereffect of logging on federal lands in the 1980s.

But a handful of studies and scientists’ repeated stories of barred owls harassing spotted owls all suggest the barred owl is taking a toll.

“If you get a room of field biologists, people who have been out in areas where barred owls are present in any number, you don’t get any disagreement about it,” Gremel said.

Shooting next?

Desperate government wildlife managers are now considering experiments of systematically shooting barred owls.

In a preliminary test in Northern California, researchers shot seven barred owls near former spotted-owl nesting sites. Spotted owls returned to all the sites.

Lowell Diller, a biologist with Green Diamond Resource Co., which owns the forest where the shootings took place, thinks it’s a worthwhile experiment, even if it’s controversial.

“As a society we may choose not to control barred owls. But we ought to do it with the knowledge of what would it take and is it feasible,” he said.

There’s a bloody history of killing one animal to help another. Brown-headed cowbirds are shot to protect songbirds, arctic foxes are killed for the sake of rare ducks, and some want to shoot sea lions feasting on Columbia River salmon.

But Forsman, of the Forest Service, has his doubts.

“You could shoot barred owls forever, and as soon as you quit they’re going to be right back.”

Politics of protection

Despite the fear of barred owls, some warn they are political fodder for those who want to see more logging.

Environmentalists charge that the Bush administration has tried to water down the Northwest Forest Plan while talking up the barred-owl threat.

In the latest move, on Tuesday the U.S. Fish and Wildlife Service issued new maps showing which Northwest forests are vital to the spotted owl’s recovery. The agency cut 1.6 million acres from its previous maps, including 400,000 acres in Washington and 1 million acres in Oregon.

The reduction in protected acreage has come under fire from environmentalists and several organizations of scientists, who argue the spotted owl’s decline makes old-growth habitat more important, because it offers the owls more refuge.

“They’re pulling the habitat rug out from underneath a declining species,” said Dominick DellaSala, chief scientist for the Oregon-based environmental group, the National Center for Conservation Science and Policy.

Service spokeswoman Joan Jewett, however, said the changes were driven by a growing scientific understanding of what the owls really need.

“There really isn’t any evidence to suggest that creating more habitat reserves will alter adult (owl) survivorship,” she said.

Ross Mickey, of the American Forest Resource Council, accuses environmentalists of trying to use the owl’s woes to lock up more forests.

“All you’re doing is … protecting more habitat for the barred owl,” said Mickey, whose group represents the timber industry.

If spotted owls vanish from some forests, it could reshape the political pressures that led to the Northwest Forest Plan.

The plan is meant to help a lot of old-growth species, but the amount of protected federal land was set with spotted owls in mind. If the birds are gone, it could be easier to whittle away at those areas, said Chuck Meslow, a retired federal wildlife biologist who helped craft the 1994 plan.

It’s on Washington’s state and private lands where the decline of spotted owls could make the most immediate difference.

The state Department of Natural Resources in 2005 put a moratorium on lifting protections for areas around abandoned spotted-owl nests. That was spurred partly by concerns that barred owls were driving them from prime habitat.

The moratorium is scheduled to expire at the end of the year.

“You can’t give up,” said DellaSala. “Giving up just opens the floodgates for more logging.”